Hydraulic pump



March 28, 1950 J. P. JOHNSON 2,501,947

nmawuc PUIIP Filed May 17, 1944 s sheets-Sheet? INVENTOR.

12 765? JaHA/sg/v Patented Mar. 1950 UNITED STATES PATENT OFFICE HYDRAULIC PUMP James P. Johnson, Shaker Heights, Ohio Application May 17, 1944, Serial No. 535,972

12 Claims. (01. 103-123) This inventionrelates to hydraulic pumps and more particularly to an improved rotary type especially adaptable for use on aircraft.

In the past, hydraulic gear pumps were used where high pressures around 1000 p. s. i. were required in the operation of landing gear, flaps, brakes, wing tips, floats, turrets, etc. and with general satisfactory results due, no doubt, to the small sizes of the aircraft, their light loads, their altitude limitations and their short cruising ranges. With the advent of larger planes, heavier loads, and higher flying. the requirements of the hydraulic system were greatly increased and as a result these hydraulic gear pumps failed at pressures ranging from 1000 p. s. i. upwards. It

was impractical to increase the size and inherent strength of the materials because this would add materially to the weight of the pump which never would meet the requirements of the U. S. Army Air Corps specifications. These gear pumps also failed during operation in cold climates like Alaska, as well as at extremely high altitudes.

With the foregoing conditions in view, it is an object of the present invention to provide an improved hydraulic rotary pump which is simple in construction, efficient in operation, and inexpensive to manufacture and assemble.

Another object of the present invention is to provide a rotary pump having a pair of inlet ports and a pair of outlet ports definitely related with a multi-lobed rotor disposed and operable for drawing fluid successively into the inlet ports and discharging the same under pressure from the outlet ports in a substantially continuous stream without pressure impulses regardless of the rotor speed.

Another object of the present invention is to provide in a rotary pump of the type referred to, an improved balanced metal rotor having axially projecting ends of relatively large diameter compared to that of the rotor and journaled in a metal enclosure of bearing material having a coefficient of expansion closely approximating that of the rotor to afford maintenance of running tolerances regardless of temperature changes.

Another object of the present invention is to provide in a rotary pump of the type referred to, a drive shaft rotatable in opposite directions and a seal therefor which is pressure actuated regardless of the direction of rotation of the rotor.

Another object of the invention is to provide in a rotary pump of the type referred to, a pressure control for the shaft seal including a pair per sides communicating with different fluid openings in the pump and their lower sides communicating with the shaft seal, the valve member on the high pressure side always closing and the one on the low pressure side always opening to relieve pressure in excess of that required to effect actuation of the shaft seal regardless of the direction of rotation of the shaft.

Another object of the present invention is to provide a rotary pump of the type referred to having a novel hollow enclosure of metal bearing material, one of the walls of which includes a removable plug for preventing collapse of the enclosure, said plug aifording ease of assembly, providing one of the pump parts, and operating as a bearing for one of the projecting ends of a rotor rotatable within said enclosure.

Another object of the present invention is to provide a rotary pump of improved construction which is adapted for operation in opposite directions without requiring any changes in the operating elements of the pump.

With the objects above indicated and other objects hereinafter explained in view, my invention consists in the construction and combination of elements hereinafter described and claimed.

Referring to the drawings:

Figure 1 is a vertical longitudinal sectional view taken substantially along line i-i in Figure 2 and showing details of a rotary hydraulic pump embodying the present invention.

of spring loaded valve members having their up- Figure 2 is an end elevational view of the pump assembly looking at the drive shaft end.

Figure 3 is an end elevational view of the pump assembly looking at the port end.

Figure 4 is a horizontal sectional view taken substantially along line 4-4 in Figure 3 and showing details of the fluid ports and plug.

Figure 5 is atransverse sectional view on an enlarged scale taken substantially along line 5-5 in Figure l and showing details of the rotor assembly Figure 6 is a transverse sectional view taken substantially along line 8-6 in .Figure 1 and showing the way in which two diametrically opposite ports communicate with one fluid opening.

Figure 'l is a fragmentary longitudinal sectional view taken substantially along lines l-l in Figure 5 and showing details similar to Figure 1 but in a different plane.

Figure 8 is a fragmentary longitudinal sectional view taken substantially along line 8-8 in Figure 3 and showing one of the spring loaded valve members in closed position because of the direction of rotation of the rotor as indicated by the arrows in other views.

Figure 9 is a fragmentary longitudinal sectional view taken substantially along line 9-9 in Figure 3 and showing the other spring loaded valve member in open position for the same reason as in Figure 8. 7

Figures 10 to 13 inclusive show the plug and the various holes and passageways formed therein; Figure 10 being a front end view; Figure 11 being a rear end view; Figure 12 being a transverse sectional view taken substantially along line |2-|2 inFlgure 10 and showing the structure through one set of ports; Figure 13 being a transverse sectional view taken substantially along line |3|3 in Figure 10 and showing the structure through the other set of ports.

Figure 14 is a fragmentary transverse sectional view taken substantially along line |4-|4 in Figure 1 and showing the way in which two different diametrically opposite ports communicate with the other of two fluid openings in the pump housing, Fig. 6 showing the Way in which two diametrically opposite ports communicate with one of such fluid openings.

In the drawings I have illustrated the invention embodied in a hydraulic rotary pump especially adapted for use on aircraft but other adaptations may be made as will be obvious to those skilled in the particular art. The pump comprises a body 20, of aluminum or like lightweight metal, having a generally circular flange 2| disposed in a transverse plane at its inner end. A tubular spacer 22, also of aluminum, is disposed in a horizontal position as'viewed in Figure 1, with one end in abutting engagement with the adjacent face of the flange 2|. A cover 23, also of aluminum, has a generally circular flange 24 disposed in a transverse plane at its inner end which is adapted for abutting engagement with the opposite adjacent end of the spacer 22. A plurality of stud bolts 25 are spaced apart angularly and extend through aligned openings provided in the flanges 2| and 24 and the spacer 22 being'detachably secured in assembled relation by nuts 26.

Due to the great range of temperatures under which the pump is required to operate as well as high pressures, it is essential that close running tolerances be maintained if the pump is to operate at its highest efliciency and to assure this an insert 21, of bronze, is provided. The insert, as more clearly shown in Figures 1, 5 and 7, has a circular portion 28 which fits tightly within the spacer 22 and abuts the inner adjacent face of r the flange 2 I. About midway, the wall of the insert 21 is reduced in diameter at 29 to provide a chamber 30 for a purpose to be later described, the reduced end abutting the inner adjacent face of the flange 24. The insert 21 is further provided with a circular extension 3| projecting axially outward from the outer face and piloted in a similarly shaped opening 32 formed at the central portion of the flange 2| for securing the insert against misalignment. The insert is further provided with a circular pump chamber 33 of suitable diameter which extends axially inward from the end 29 and terminates in an inner wall face 34 positioned transversely with respect to the bore axis. A pair of narrow slots 35 are formed in the insert 21, each of which extends entirely through the wall of the end 29 affording communication with the chamber 30 and through the adjacent end of the portion 28 terminating in the plane of the inner wall face 34. These slots 35 are on diametrically opposite sides of the bore axis and are parallel to the longitudinal axis of the bore 33.

The insert 21 is further formed with a pair of semi-circular holes 36, of small diameter, which extend inwardly from the end 29 to the wall face 34 and project outwardly from the inner peripheral wall of the bore 33. This pair of holes 36 is arranged relatively in diametrically opposite parallel relation on opposite sides of the axis of bore 33 and angularly spaced on one side from the adjacent slots 35 any desirable angle but preferably as close as practicable to slots 35. A

second pair of semi-circular holes 31, of substantially the same size-as the holes 36, extend inwardly from the end 29 to the wall face 34 and project outwardly from the inner peripheral wall of the bore 33. This pair of holes 31 is arranged relatively in diametrically opposite parallel relation on opposite sides of the axis, and angularly spaced on the other side from the adjacent slots 35 any desirable angle but preferably as close as practicable to slots 35. This is shown more clearly in Figures 5 and '7.

The cover 23 is formed with a circular bore 33, of substantial diameter, which extends axially outwardly from the inner face of the flange 24 terminating in an end wall 39 disposed transversely of the bore axis. The cover 23 is further formed with an annular groove 40 projecting outwardly from but in encircling relation about the inner periphery of the bore 38 for a purpose to be later described.

A circular plug 4|, of bronze, fits securely in the cover bore 38 and has its outer end 42 formed to seat solidly against the end wall 39 while its inner end 43 is finished flat but projects slightly beyond the inner face of the flange 24. The projecting end of the plug 4| securely fits into an annular recess 34 of complementary shape formed on the adjacent end 29 of the insert to prevent or materially reduce collapse of the latter. The foregoing detailed construction of the insert 21 and plug 4| constitutes the heavy bronze enclosure for the pumping unit which is sufiicient to withstand high pressures and a great range of temperatures without affecting predetermined running tolerances.

The plug 4| is suitably ported for the purpose intended and is more clearly illustrated in Figures 10 to 13 inclusive to which reference should be had. A pair of holes 45 are drilled in the plug and extend axially rearwardly from the front face 43 to about the middle of the plug where they communicate with outwardly directed peripheral slots 46 as shown in Figure 12. The holes 45 are disposed in diametrically opposite relation on opposite sides of the axis of the plug and are adapted for longitudinal alignment with the semi-circular holes 36 when assembled. A second pair of holes 41 are drilled in the plug and extend axially rearwardly from the front face 43 to adjacent the rear face 42 where an arcuate shaped slot 48 is formed on the latter in a manner to afiord communication between the inner ends of the holes 4'! as more clearly shown in Figure 13. The holes 41 are disposed in angular spaced relation with respect to the holes 45 but are disposed in diametricall opposite relation on opposite sides of the axis of the plug and are adapted for longitudinal alignment with the semi-circular holes 31 when assembled.

The cover 23 has a boss 49, generally of figure eight shape as viewed from the port end of the pump, projecting outwardly at the lower portion 8 thereof. 'l'hebossllhasaninteriorlyscrcw threaded fluid opening I formed on one side thereof which extends inwardly a suitable distance terminating in a circular opening II, an annular shoulder I2 and a circular opening it of relatively smaller diameter which communicates with the arcuate slot ll as more clearly shown in Figure 4. The boss ll also has an interiorly screw threaded fluid opening it formed on the other side thereof which, likewise, extends inwardly a suitable distance terminating in a circular opening 55, an annular shoulder I8 and a circular opening 51 of smaller diameter. A small opening II in the cover 23 aflords communication between the bottom of the circular opening 51 and the annular groove 40. It should involve no difliculty in following the communicating passageways through the fluid openings, in the plug ll and in the insert 21 from the detailed description so far given and any further explanation will be confined to the operation of the pump later to be described.

As the adapters and nuts for the threaded openings 50 and it are identical a description of one will suflice. A tubular adapter 59 has its outer end positioned coaxially within the opening 50 and its inner end formed with an outwardly projecting circumferential flange 60 adapted to seat securely on the shoulder 52, the extreme end being formed with a short extension 6| fitting snugly within the opening 53. A nut 62 has anexteriorly screw threaded skirt 63 which slidably flts over the outside of the tubular adapter 59 and threadably engages the opening the end of the skirt 83 abutting the top side of the flange 60 to secure the adapter against accidental removal. The outer end of the adapter is formed with a pipe tap G4 on its in side for connection with a suitable fluid conduit not shown.

A rotor 85, of steel or like material, shown more clearly in Figures 1, 5 and 7, is rotatably disposed concentrically within the pump chamber bore 33 of the insert 21 and has its opposite end faces in running engagement with the adjacent end wall 34 of said insert and wall ll of plug 4| respectively. The peripheral wall of the rotor 65 is preferably in the form of a multi-lobed cam, three being herein employed, the peaks 66 extending longitudinally and substantially equally spaced apart relatively in angular relation of 120 degrees with intervening depressions defining with the bore 33, three chambers 61 of small but substantially equal volumetric capacity, the peaks being rotatably engageable with the inner peripheral wall of the pump chamber bore 33. The peaks 66 are arcuately formed for a short distance in accordance with the curvature of the pump chamber bore and the intermediate surfaces are formed to a curvature by common radii the centers of which are eccentrically disposed with respect to the axis of rotation of the rotor, in such'a manner that the exterior surface recedes from each peak 66 toward the intermediate low point where adjacent surfaces coincide thus providing three non-communicating fluid chambers 81 of small but substantially equal volumetric capacities. The rotor 85 has circular extensions 68, of relatively large diameter, projecting axially outward from the opposite ends thereof which are rotatably journaled in aligned openings 89 formed in the adjacent end wall of the insert 21 and III formed in the plug 4| in the manner shown in Figures 1 and '1. The rotor Bl has an opening Ii extending centrall through the extensions 00 and body of the rotor, a plurality of inwardly projecting teeth 12 intermediate the ends of such opening H affording a spline connection. The coeilicient of expansion of the steel rotor and bronze enclosure is closely related so that changes in temperatures will not materially affect the tolerances of the assembled parts and inasmuch as the rotor extensions 68 are of relatively large diameter a better bearing is aflorded with less wear over a longer period of time.

A pair of relatively thin steel blades ll are slidably but non-rotatably mounted in the transversely aligned slots 35 formed on the insert 21 and have their inner ends engageable at diametrically opposite sides of the peripheral wall.

of the rotor for eflecting reciprocation of the blades 13, the blades also being adapted to divide the pump chamber into separate non-communicating portions. To effect contact between the inner ends of the blades 13 and the exterior non-cylindrical cam face of rotor 65, a looped resilient spring member 14 is disposed for free oscillating movement in the chamber 30 and has portions removably disposed in recesses I! provided in the outer central portion of the blades in such a manner as to afford unitary movement. If the cam face of the rotor is formed accurately the spring member 14 will not flex but oscillate as a unit. If, on the other hand, such cam face is not formed accurately,

the blades can still be made to engage the rotor face by suitably preloading the ring 14. The peaks 66 and depressions therebetween are positioned relatively in such a manner that the same dimension prevails between all diametrically opposite points on the peripheral wall or cam face of rotor 65 when passing through the axis of rotation of the rotor 65. It is to be further noted that two ports 36 and 31 are located in each separate pump chamber portion divided by the blades and that adjacent ports therein are spaced apart relatively a greater distance than the angular spacing of the peaks on the rotor so as to prevent communication therebetween in all rotative positions of the latter.

Any suitable means may be adapted for positively drivin the pump rotor 65, but preferably a simple and efilcient construction is shown in Figures 1 and 2. The body 20 has an attaching flange 15 of square shape at its outer end which is disposed transversely and has openings 16 at the corners thereof to adapt the pump for attachment to a mounting pad. The body 20 is further formed with a bore 11 which extends axially inward from the flange i5 and communicates with the opening 32 formed in the flange II. The bore i1 is of larger diameter at its outer end and is interiorly screwthreaded for a greater portion of its length. A circumferentially extending groove 18 is formed at the inner end of the bore I1 at the base of the threads'and is provided to receive oil in a manner to be later described. Beyond the groove, the bore ll communicates with the bore 82 which is of relatively smaller diameter thus providing a seat or shoulder 19 for a purpose to be described.

A drive shaft 80, of steel or other suitable material, extends centrally through the bore 11 and has a reduced end portion ll provided with external splines which slidably fit within the internally splined opening 12 in the rotor in such a manner as to permit slight independent axial movement of the shaft but to prevent relative independent rotation with respect to the rotor I,

The shaft 88 is further provided with a steel seal ring 82 of circular shape, disposed adjacent the bore 32 and held against relative axial movement by a snap ring 83 removably secured in a circumferential groove 84 formed on the shaft. The outer face of the ring 82 is machined flat and true to provide a seal face 85.

A bronze sleeve 86 is loosely mounted upon the shaft 88 and has a laterally extending circular flange 81 at its inner end, the inner face of which is machined flat and true to provide a seal face 88 which is adapted for engagement with the seal face 85 on the rotatable shaft 88 to effect a fluidtight seal therebetween.. A plug 89 is exteriorly screwthreaded and insertable in the screwthreaded portion of the bore I1 and has a circular opening within which the drive shaft 88 is rotatably disposed but in spaced relation. The inner end of the plug 89 is provided with an annular extension 98 projecting beyond the recess 18 and having its inner end abutting the shoulder I9 formed on the bottom of the bore 11. A flexible resilient seal ring 9|, preferably of synthetic rubber or similar material, is disposed within the space between the outer face of the flange 81 and the bottom of the plug, the latter affording a rigid abutment for the ring. This construction affords a yieldable abutment for the flange 81 and due to the fact that the sleeve 88 is loosely mounted upon the drive shaft, the sealing face of the flange 81 can at all times adapt itself to. any angular disposition (within practical limits) which the flange 81 on the drive shaft may assume without affecting its sealing"characteristics.

The sleeve 86 is prevented from rotation on the drive shaft by means of a pair of tongues 92 constituting extensions of the body of the sleeve which are positioned on diametrically opposite sides, they being positioned for sliding movement within a pair of grooves 93 cut in the adjacent portion of the plug 89.

The plug 89 at its front end is provided with a plurality of slots 94 centrally disposed and spaced apart angularly about its axis and are adapted to selectively receive the end 95 of a locking plate 96. The plug 89 is further pro vided with a plurality of tapped openings 91 positioned in angular alignment with the slots 94 but outwardly therefrom and the locking plate 93 has an opening for selective alignment with the tapped openings 91. A screw 98 secures the locking plate in proper position in any of the selected slots 94. The attaching flange I is provided with a plurality of slots 89 angularly spaced apart relatively about the axis of the shaft and these slots are likewise selectively adapted to receive the plate 96. There are preferably a different number of slots 99 in the attaching flange than the number of slots 94 in the plug. The outer end of the shaft 88 projects beyond the attaching flange and has a toothed pinion I88 formed thereon adapted for connection with any suitable power drive means.

When the pump is operating the pressure created by the fiuid'therein will cause an outbore II at the cover end and has an integral stem I82 projecting axially outward which is slidably mounted in a bore I88 formed in the adjacent wall of the cover 23. A coiled spring I84 encircles the stem and has one end abutting the adjacent end of the plunger and the other end abutting the adjacent wall 01' the cover to exert an outward force on the plunger IN. The inner end of the plunger I8I has a bore I to receive a ball I86 which engages the spline end of the shaft and exerts an axial force thereon which is sumcient to maintain the sealing faces of the shaft seal effectively without the presence of. fluid pressures. The end of the plunger is turned in to prevent the ball I86 from displacement.

As this pump is designed for handling high pressures especially and operation in either direction of rotation, it is desirable that the fluid pressure for actuating the seal about the drive shaft 88 be maintained at a pressure for best effecting sealing without injury to the parts and afford relief when the pressure rises in excess of that desired regardless of the direction of rotation of the pump rotor. While any suitable means may be employed, the one illustrated in the drawings has many novel features and is efficlent in operation. Preferably, the cover 23 is formed with an extension I81 on its outer end and directly above the boss 49 as more clearly shown in Figure 3. A pair of interiorly screwthreaded openings I88 and I89 extend inwardly from the top of the extension I81 and are spaced apart relatively in a transverse plane. The opening I88 as shown more clearly in Figure 8 terminates adjacent the top of the plug H but communicates with an axial bore 8 of slightly smaller diameter thus providing a horizontal seat or shoulder II I at the base of the opening I88. The bore H8 terminates short of the opening I8 in the plug 4I and has a cylindrical extension II2 of smaller diameter projecting outwardly from its bottom, the top being flat to provide a valve seat H3. The extension II2 has an opening II4 extending centrally therethrough which intersects with a horizontally disposed opening H5 formed valve member II6, the spring normally urging A plug H8 is the valve member off its seat. threadably mounted in the opening I88 and when tightened engages the shoulder III. The plug II8 has ends II9 projecting into the bore II8 to provide a stop for upward movement of the valve member II6 which likewise permits free flow of fluid therethrough. An opening I28 is drilled in the cover 23 to afford communication between the top side of the valve member H6 and the arcuate slot 48 on the plug 4I. This establishes communication with the ports3'l of the pump chamber and as the rotor rotates in one direction, as indicated by the arrows, the pressure from the high side closes the valve member II6 cutting off communication through the openings H4 and 5 which communicate with the plug opening 18 in turn communicating with the pressure chamber at the seal.

The other opening I88, more clearly shown in 9 Figure 9, has precisely the same'arrangement as the before described opening I03 and terminates adjacent the top of the plug 4I but communicates with an axial bore I2l of slightly smaller diameter thus providing a horizontal seat or shoulder I22 at the base of the opening I99. The

bore I 2I terminates short of the opening 19 in the plug 4I and has a cylindrical extension I23 of smaller diameter projectingoutwardly from its bottom, the top being flat to provide a valve seat I24. The extension I23 has an opening I26 extending centrally therethrough which intersects with a horizontally disposed opening I26 formed in the inner wall of the cover in a manner to afford communication between the opening in the plug and the bore I2I in the cover. A disc valve member I21 is slidably mounted in the bore I2I and is adapted to, when open, unseat the valve seat I24 to efiect communication through the openings I26 and I26. A coiled spring I28 encircles the extension I23 and has its lower end abutting the bottom of the bore I2I and its upper end abutting the under side of the valve member I21, the spring normally urging the valve member oflf its seat. A plug I29 is threadably mounted in the opening I09 and when tightened engages the shoulder I22. The plug I29 has ends I39 projectiug into the bore I2i to provide a stop for upward movement of the valve member I21 which likewise permits free flow of fluid therethrough. An opening I3I is drilled in the cover 23 to afford communication with the top side of the valve member I21 and a similar aligned opening I32 is drilled in the plug H to afl'ord communication with the openings 45 and 46 in the plug 4|. This establishes communication with the ports 36 oi the pump chamber and as the rotor rotates in one direction, as indicated by the arrows, the pressure from the low side opens the valve member I21 thereby establishing communication through the openings I25 and I26 which communicate with the plug opening 10 in turn communicating with the pressure chamber at the seal. The springs Ill and I28 may be replaced at will, if a greater or lesser tension is desired which will govern the pressure required to actuate the seal and at which the excess will be relieved by the relationship of the valve member depending upon the direction of rotation of the rotor.

The brief description of the operation of the pump should suflice for a clearer understanding of the seal valve operation without further'detailed explanation. The rotary hydraulic pump is designed for use in hydraulic systems employed on aircraft and is positively driven through the 55 drive shaft 80 which is directly connected with the engine. As the shaft rotates, in the direction indicated by the arrows, the rotor 65 is caused to rotate rapidly in the same direction, with the result that fluid is drawn into the inlet ports 36 (by reason of the suction created by the rapidly rotating peaks 66) and discharged under pressure from the adjacent outlet ports 31. The pairs of ports 36 and 31 in each half pump chamber portion are kept non-communicative by the pair of diametrically opposite blades 13 which engage the outer peripheral wall of the rotor, which blades are reciprocated as the rotor rotates to compensate for the changing positions of the fluid chambers 61. The discharge of fluid is substantially continuous and free from pressure impulses due to shape of the rotor cam face and the double inlet and outlet arrangement. The fluid flowing in all of the communicating holes and passageways connected with the inlet ports 36 1S 9! low pressure and this includes the valve member I21 which is unseated to effect communication between the seal pressure chamber and the holes '46 and 46 in the plug H to afford relief of the fluid pressure at the seal in excess of that for which the valve is set to function. At the same time the fluid flowing in all of the communicating holes and passageways connected with the outlet ports 31 is of high pressure and this includes the valve member II6 which is seated, against the spring tension, to cut oil communication between the seal pressure chamber and the arcuate slot 48 in the plug 4I. This prevents any flow of fluid from the opening 10 in the plug 4I through the holes I I6 and I I 4.

Now when the pump is to operate in the other direction it is only necessary to rotate the shaft 30 in the opposite direction, or contra to the arrows, and the rotor 65 is caused to rotate in the same direction with the result that fluid is drawn into the inlet ports 31 (formerly the outlet ports in reverse rotation) by reason of the suction created by the rapidly rotating peaks 66, and discharged under pressure from the adjacent outlet ports 36, (formerly the inlet ports in reverse rotation) The rest of the structure bears the same relation and operates in the same manner. However the fluid flowing in all of the communicating holes and passageways connected with the inlet ports 31 is of low pressure and this includes the valve member I I6 which is unseated to effect communication between the seal pressure chamber and the arcuate slot 48 on the plug H to afford relief of the fluid pressure at the seal in excess of that for which the valve is set to function. At

the same time the fluid flowing in all of the communicating holes and passageways connected with the outlet ports 36 (formerly the inlet ports in reverse rotation), is of high pressure and this includes the valve member I21 which is seated, against the spring tension, to cut off communication between the seal pressure chamber and the holes 45 and 46 in the plug II. This prevents any flow of fluid from the opening 19 in the plug 4I through the holes I25 and I26. The operation of these valves is entirely automatic and operates to relievev the seal pressure regardless of the direction of rotation of the rotor.

While I have described the preferred embodiment of the invention it is to be understood that I am not to be limited thereto inasmuch as changes and modifications may be resorted to without departing from the spirit of the invention as defined in the appended claims.

What is claimed is:

l. A rotary pump comprising a housing, a cover member removably connected to said housing, an insert securely fitted into said housing and formed with a. pump chamber bore open at one end-of said insert, a plug securely fltted into said cover member and formed with a projection removably piloted within said insert, and a rotor rotatably disposed in such bore, said cover member being formed with a fluid inlet passageway and a fluid outlet passageway affording communication respectively with difl'erent sides of the pump chamber bore. 1

2. A rotary pump comprising a housing, a cover member removably connected to said housing, said housing and cover member defining a chamber with one end wall in said housing and another end wall in said cover member, an insert securely fltted into such chamber with one end thereof abutting said one end wall in said housing, said insert being formed with an axially extending pump chamber bore open at the other end of said insert, a plug securely fitted into such pump chamber with one end thereof abutting said another end wall in said cover member, and with the other end thereof removably piloted within said insert, and a rotor rotatably disposed in such bore, said cover member being formed with a fluid inlet passageway and a fluid outlet passageway afiording communication respectively with diflerent sides of the pump chamber bore.

3. A rotary pump comprising a housing, a cover member removably connected to said housing, an insert securely fitted into said housing and defining therewith an annular chamber around said insert, said insert being formed with an axially extending pump chamber bore open at one end of said insert and a pair of diametrically opposed radial slots therethrough extending axially from said one end toward the other end thereof, a plug securely fitted into said cover member and formed with a projection removably piloted within said insert to prevent collapse of the latter under high pressures, a rotor rotatably disposed in such bore having a non-circular peripheral wall in the form 01' a three-lobe cam, the peaks of the cam being equally Spaced apart about the axis 01 the rotor and having a running fit with the inner peripheral wall of such bore, a pair of blades slidably disposed in such slots and having inner edges contacting with the peripheral wall of said rotor for effecting reciprocation of said blades in response to rotation of said rotor and for dividing the pump chamber bore into separate non-communicating portions and 'outer edges projecting into such annular chamber around said insert, and a resilient ring disposed for free oscillatory movement in the annular chamber and operatively connected to said blades for exerting a yieldable pressure to maintain contact between the blades and rotor as aforesaid, said cover member being formed with a fluid inlet passageway and a fluid outlet passageway afi'ording communication respectively with the separate non-communicating portions of the pump chamber bore.

4. A rotary pump comprising a housing, a cover member removably connected to said housing, an insert securely fitted into said housing and defining therewith an annular chamber around said insert, said insert being formed with an axially extending pump chamber bore open at one end of said insert and radial slots therethrough extending axially from said one end toward 'the other end thereof, a plug securely fitted into said cover member and formed with a projection removably piloted. within said insert to prevent collapse of the latter under high pressures, a rotor rotatably disposed in such bore having a noncircular peripheral wall in the form of a plurallobe cam, the peaks of the cam being equally spaced apart about the axis of the rotor and having a running fit with the inner peripheral wall of such bore, blades slidably disposed in such slots and having inner edges contacting with the peripheral wall of said rotor for effecting reciprocation of said blades in response to rotation of said rotor and for dividing the pump chamber boreinto separate non-communicating portions and outer edges projecting into such annular chamber around said insert, and means in the sageway affording communication respectively with the separate non-communicating portions of the pump chamber bore.

5. The combination with a rotary pump of the type including a pair of diametrically opposed blades in contact with a three-lobe non-circular peripheral wall of a rotor rotatable in a cylindrical pump chamber bore with which the lobes of said rotor have a running flt, said blades dividing the bore into separate noncommunicating portions, of a housing, a cover member removably connected to said housing, an insert carrying said blades and securely fitted into said housing and formed with such pump cham ber bore, a plug securely fitted into said cover member and provided with a projection removably piloted in said insert to prevent collapse of the latter under high pressures, said cover member being formed with a fluid inlet pasageway and a fluid outlet passageway affording communication respectively with the separate non-communicating portions of the pump chamber bore, said insert being formed with a pair of diametrically opposed inlet passages and a pair of diametrically opposed outlet passages each passage of each pair being in close proximity with one of the blades but on opposite sides of a plane through said blades.

6. The combination with a rotary pump of the type including a pair of diametrically opposed blades in contact with a. three-lobe non-circular peripheral wall of a rotor rotatable in a cylindrical pump chamber bore with which the lobes of said rotor have a running fit, said blades dividing the bore into separate non-communicating portions, of a housing, acover member removably connected to said housing, an insert carrying said blades and securely fitted into said housing and formed with such pump chamber bore, a plug securely fitted into said cover member and provided with a projection removably piloted in said insert to prevent collapse of the latter under high pressures, said cover member being formed with a fluid inlet passageway and a fluid outlet passageway affording communication respectively with the separate non-communicating portions of the pump chamber bore, said insert being formed with a pair of diametrically opposed inlet pasannular chamber operatively connected to said aforesaid, said cover member being formed with a fluid inlet passageway and a fluid outlet passages and a pair of diametrically opposed outlet passages each passage of each pair being in close proximity with one of the blades but on opposite sides of a plane through said blades, said cover member being formed with an annular groove encircling said plug, said plug being formed with a pair of passages including axially extending portions leading to one pair of passages in said insert and lateral openings leading to such annular groove, one of the passageways in said cover member leading to such annular groove.

7. The combination with a rotary pump of the type including a pair of diametrically opposed blades in contact with a three-lobe non-circular peripheral wall of a rotor rotatable in a cylindrical pump chamber bore with which the lobes of said rotor have a running fit, said blades dividing the bore into separate non-communicating portions, of a housing, a cover member removably connected to said housing, an insert carrying said blades and securely fitted into said housing and formed with such pump chamber bore, a plug securely fitted into said cover member and provided with a projection removably piloted in said insert to prevent collapse of the latter under high pressures, said cover member being formed with a fluid inlet passageway and a fluid outlet passageway aflording communication respectively with the separate non-communicating portions of the pump chamber bore. said insert being formed with a pair of diametrically opposed inletpassages and a pair oi' diametrically opposed outlet passages each passage of each pair being in close proximity with one'of the blades but on opposite sides of a plane through said blades, said plug being formed with a pair of axially extending passages therethrough in communication with one pair of passages in said insert and with an arcuate groove connecting such axially extending Passages to one another, one of. the passageways in said cover member leading to such arcuate groove.

8. The combination with a rotary pump of the type including a pair of diametrically opposed blades in contact with a three-lobe non-circular peripheral wall of a rotor rotatable in a cylindrical pump chamber bore with which the lobes of said rotor have a running fit, said blades dividing the bore into separate non-communicating portions,

' of a housing, a cover member removably connected to said housing, an insert carrying said blades and securely fitted into said housing and formed with such pump chamber bore, a plug securely fitted into said cover member and provided-with a projection removably piloted in said insert to prevent collapse of the latter under high pressures, said cover member being formed with a fluid inlet passageway and a fluid outlet passageway affording communication respectively with the separate non-communicating portions of the pump chamber bore, said insert being formed with a pair of diametrically opposed inlet passages and a pair of diametrically opposed outlet passages each passage of each pair being in close proximity with one of the blades but on opposite sides of a plane through said blades, said cover member being formed with an annular groove encircling said plug, said plug being formed with two pairs of passages, one pair including axially extending portions leading to one pair of passages in said insert and lateral openings leading to such annular groove, and the other pair including axially extending portions leading to the other pair of passages in said insert and an arcuate groove Joining such other pair of passages in said plug, the passageways in said cover member respectively leading to such annular groove and such arcuate oove. e

9. A rotary pump comprising a housing, a cover member removably connected to said housing, an insert securely fitted into said housing and formed with a pump chamber bore open at one end of said insert,- a plug securely fitted into said cover member and formed with a projection removably piloted within said insert, a rotor of noncircular contour rotatable in said insert and having a running fit with such bore at a plurality of equally spaced points, means carried by said insert contacting said rotor and dividing said bore into separate non-communicating portions, said insert being formed with an inlet and an outlet passage in each such portion spaced apart more than the equally spaced points of contact of said rotor with such bore, said cover member being formed with a fluid inlet passageway and a fluid outlet passageway, and said plug being formed with passages leading from the passageways in said cover member to the passages in said insert.

10. A rotary pump comprising a housing, a cover member removably connected to said housing, an insert securely fitted into said housing and formed with a pump chamber bore open at one end of said insert, a plug securely fitted into said cover member and formed with a projection removably piloted within said insert, arotor of noncircular contour rotatable in said insert and having a running fit with such bore at a plurality of equally sp ed points, means carried by said insert contactingaid rotor and dividing said bore into separate non-communicating portions, said insert being formed with an inlet and an outlet passage in each such portion spaced apart more than the equally spaced points of contact of said rotor with such bore, said cover member being formed with a fluid inlet passageway and a fiuid outlet passageway, said plug being formed with passages leading from the passageways in said cover member to the passages in said insert, said cover member being formed with an annular groove encircling said plug, some of the passages in said plug including axially extending portions leading to passages in said insert and lateral openings leading to such annular groove, one of the passageways in said cover member leading to such annular groove.

11. A rotary pump comprising a housing, a cover member removably connected to said housing, an insert securely fitted into said housing and formed with a pump chamber bore open at one end of said insert, a plug securely fitted into said cover member and formed with a projection removably piloted within said insert, a rotor of noncircular contour rotatable in said insert'and having a running fit with such bore at a plurality of equally spaced points, means carried by said insert contacting said rotor and dividing said bore into separate non-communicating portions, said insert being formed with an inlet and an outlet passage in each such portion spaced apart more than the equally spaced points of contact of said rotor with such bore, said cover member being formed with a fiuid inlet passageway and a fluid outlet passageway, said plug being formed with passages leading from the passageways in said cover member to the passages in said insert, some of the passages in said plug including axially extending portions leading to passages in said insert and an arcuate groove joining such portions, one of the passageways in said cover member leading to such arcuate groove.

12. A rotary pump comprising a housing, a cover member removably connected to said housing, an insert securely fitted into said housing and formed with a pump chamber bore open at one end of said insert, a plug securely fitted into said cover member and formed with a projection removably piloted within said insert, a rotor of noncircular contour rotatable in said insert and having a running fit with such bore at a plurality of equally spaced points, means carried by said insert contacting said rotor and dividing said bore into separate non-communicating portions, said I insert being formed with an inlet and an outlet passage in each such portion spaced apart more than the equally spaced points of contact of said rotor with such bore, said cover member being formed with a fluid inlet passageway and a fluid outlet passageway, said plug being formed with passages leading from the passageways in said cover member to the passages in said insert, said cover member being formed with an annular groove encircling said plug, said plug being formed with passages some of which include axially extending portions leading to certain of the passages v in said insert and lateral openings leading to such annular groove and others of which includeaxially extending portions leading to certain other 15 v of the passages in said insert and an arcuate groove Joining such last-named axially extending portions, the passageways in said cover member respectively leading to such annular groove and such. arcuate groove. K

JAMES P, JOHNSON.

REFERENCES CITED file of this patent:

Number 16 UNITED STATES PATENTS Name Date Jaworowski Mar. 2'1, 1933 Helmer Dec. 21, 1937 Magrum, et a]. Jan. 25, 1944 Chisholm Feb. 6, 1945 Chisholm Apr; 10, 1945 Davis Jan. '1, 1946 Chisholm Mar. 12, 1946 Johnson Oct. 26, 1948 Johnson Oct. 26, 194? 

